Lakes & inland seas of the world

Known forDrained for cotton, and the standard cautionary tale

Diverting the Amu Darya and Syr Darya for cotton drained it — the standard case study in irrigation-driven ecological collapse.

Settinglake · Salt lake

Known forThe largest lake on earth, and a thirty-year legal argument

The largest enclosed body of water on earth — a landlocked remnant of the ancient Paratethys Ocean, saline but not oceanic, and about 28 m below sea level. Whether it is legally a sea or a lake decided how its oil and gas were divided; the five littoral states settled it in 2018 with a special status that is neither.

Settingendorheic sea · brackish · below sea level

For the examThe 2018 Aktau Convention gave it a special legal status: the surface is shared like a sea, the bed is divided like a lake. Its level is falling fast, which is a live regional issue.

Known forThe lowest land surface on earth

The lowest land surface on earth, about 430 m below sea level, and among the saltiest water bodies.

Settinglake

For the examLowest point on land. Fed by the Jordan, with no outlet — which is why it is hypersaline.

Known forThe largest lake entirely inside Canada

The largest lake entirely within Canada, straddling the Arctic Circle on the Canadian Shield and ice-covered for eight months of the year.

Settingglacial lake · Arctic · shield

Known forA terminal salt lake shrinking into a dust hazard

The largest saltwater lake in the western hemisphere, a shrunken remnant of glacial Lake Bonneville with no outlet, so everything that flows in stays. Water diversion and drought took it to a record low in 2022, exposing lakebed laden with arsenic that blows into Salt Lake City.

Settingendorheic lake · hypersaline · exposed lakebed

For the examTerminal lake: inflow only, evaporation out, so salts concentrate. It is the American parallel to the Aral, with the same exposed-bed dust problem.

Known forNorth America's deepest lake

The deepest lake in North America at 614 m, and the source of the Mackenzie — the continent's longest river system after the Mississippi.

Settingglacial lake · deep · shield

Known forThe mountain lake that never freezes

A deep, slightly saline lake at 1,607 m in the Tian Shan that never freezes — its name means warm lake — because of its depth, its salinity and geothermal inflow. It is the second largest mountain lake in the world after Titicaca.

Settingendorheic mountain lake · saline · very deep

Known forA fifth of all unfrozen fresh water, in one rift

The deepest and oldest lake on earth, holding about a fifth of all unfrozen fresh water — a rift lake.

Settinglake

For the examDeepest lake. Tanganyika is second. Both are rift lakes; Superior is glacial.

Known forThe lake that is fresh at one end and salt at the other

A closed lake that is fresh at one end and saline at the other: the Ili river enters the western basin and dilutes it, while a narrow strait restricts mixing with the salty east. It is shrinking as the Ili is drawn on in China.

Settingendorheic lake · half fresh half saline · shrinking

For the examThe Ili rises in Xinjiang, so Balkhash is a transboundary problem with China — the pattern that also affects the Irtysh.

Known forNine tenths gone since the 1960s

Shrunk by about 90 per cent since the 1960s — the standard case study in desiccation and shared-basin governance.

Settinglake

Known forThe shallowest Great Lake, and its algal blooms

The shallowest and warmest Great Lake, which is why it warms fast, freezes over, and suffers the worst algal blooms — phosphorus runoff from intensive agriculture in its basin produces a large toxic bloom most summers. It drops 51 m to Lake Ontario over Niagara Falls.

Settingglacial lake · shallow · eutrophic

For the examEutrophication from agricultural phosphorus is the mechanism, and Erie is its most cited large-lake example. Its shallowness is why it responds fastest of the five.

Known forAustralia's lowest point, and dry most years

Australia’s lowest point and largest lake — dry most years, and the centre of the largest internal drainage basin in the world.

Settinglake · Salt lake

Known forManitoulin — the largest island in any lake

The Great Lake with the longest shoreline, and the one holding Manitoulin — the largest island in any lake in the world, which itself contains lakes containing islands.

Settingglacial lake · Great Lakes system · freshwater

Known forThe lake that holds an explosion, and generates power from it

A rift lake holding an enormous dissolved load of methane and carbon dioxide in its deep water, trapped by stable density layering. A disturbance could release it catastrophically, as happened at Lake Nyos in 1986; Rwanda instead extracts the methane for electricity.

Settingrift lake · meromictic · gas-charged

For the examLimnic eruption is the hazard, and Lake Nyos in Cameroon in 1986 is the case where it happened. Nyiragongo above Kivu is the volcano that could trigger it.

Known forEurope's largest lake

The largest lake in Europe, in a glacially gouged basin north-east of St Petersburg. Its frozen surface was the Road of Life that supplied Leningrad through the siege.

Settingglacial lake · boreal · freezes over

Known forMore fish species than any lake on earth

The southernmost of the great African rift lakes and the one with more fish species than any other lake on earth — several hundred cichlids, almost all endemic, which makes it the standard example of an adaptive radiation in fresh water.

Settingrift lake · very deep · endemic cichlids

For the examAdaptive radiation: one ancestral lineage filling many niches in isolation. Malawi, Tanganyika and Victoria are the three great cichlid lakes and Victoria's radiation is the youngest and fastest.

Known forThe oil lake, and the world's lightning capital

A large brackish inlet connected to the Caribbean by a narrow strait — argued over as lake or lagoon. It sits above one of the richest oil basins in the world, and the Catatumbo river mouth at its southern end has more lightning than anywhere else on earth.

Settingcoastal lagoon · brackish · oil province

Known forThe only Great Lake wholly in the United States

The only Great Lake entirely within one country. Hydrologically it and Lake Huron are one lake at one level, joined by the deep Straits of Mackinac — they are counted separately by convention, not by physics.

Settingglacial lake · Great Lakes system · freshwater

For the examMichigan and Huron share a surface level and are technically one body. Superior, Michigan, Huron, Erie, Ontario — HOMES is the usual mnemonic.

Known forThe lake with sharks, and a canal that was never dug

The largest lake in Central America, holding freshwater bull sharks that reach it up the San Juan river. A Chinese-backed interoceanic canal through it was granted in 2013 and its concession was formally cancelled in 2024 without a metre being dug.

Settingtectonic lake · freshwater · volcanic islands

Known forThe Great Lakes' outlet to the Atlantic

The smallest Great Lake by surface and the last before the St Lawrence, so it is the system's outlet to the Atlantic. The Welland Canal beside it lets ships bypass Niagara Falls.

Settingglacial lake · outlet basin · freshwater

Known forThe largest freshwater lake by surface

The largest freshwater lake by surface area, and part of the Great Lakes–St Lawrence system.

Settinglake

Known forWhere the Blue Nile begins

Ethiopia's largest lake, dammed behind a lava flow on the Ethiopian Highlands, and the source of the Blue Nile.

Settingvolcanic-dammed lake · highland · monastic islands

Known forThe second deepest lake on earth

The second deepest and longest freshwater lake, in the western branch of the East African Rift.

Settinglake

Known forThe highest large navigable lake

The highest navigable lake in the world, on the Peru–Bolivia altiplano.

Settinglake

Known forThe caldera of the largest eruption in two million years

The largest volcanic lake in the world, filling the caldera of the largest known eruption in the last two million years — Toba, about 74,000 years ago, which put enough sulphur into the stratosphere to cool the planet for years. Samosir island in it was pushed up by later resurgence.

Settingcaldera lake · resurgent dome · very deep

For the examToba is the standard supervolcano case with Yellowstone. The Toba catastrophe hypothesis links it to a genetic bottleneck in early humans, though the evidence is contested.

Known forThe world's largest desert lake, and the Cradle of Mankind

The largest permanent desert lake in the world, in the Kenyan rift, fed almost entirely by the Omo river from Ethiopia. Ethiopia's Gibe III dam and the sugar irrigation below it have cut that inflow, and the lake is falling. Its shores hold some of the richest early-hominin fossil beds anywhere.

Settingrift lake · desert · saline and falling

For the examTurkana depends on the Omo for about 90% of its inflow, which makes an Ethiopian dam a Kenyan problem — a transboundary case with no treaty.

Known forThe Middle East's largest lake, mostly gone

Once the largest lake in the Middle East, a hypersaline terminal lake in north-west Iran. Damming its feeder rivers and groundwater pumping shrank it by about 90% by 2015; a restoration programme brought some water back, but drought has driven it near-dry again.

Settingendorheic lake · hypersaline · shrinking

For the examThe salt-dust health hazard from its exposed bed is the same failure mode as the Aral and the Great Salt Lake — three cases of one mechanism.

Known forThe soda lake behind a lava dam

Türkiye's largest lake, dammed by a lava flow on the Anatolian Plateau, with no outlet and water so alkaline it is soapy — only one fish species tolerates it.

Settingendorheic lake · highly alkaline · volcanic-dammed

Known forAfrica's largest, and a downwarp rather than a rift

Africa’s largest lake and the source of the White Nile — a shallow depression, not a rift lake.

Settinglake

Known forA lake sealed under four kilometres of ice

The largest subglacial lake on earth, sealed under about 4 km of Antarctic ice and isolated from the atmosphere for millions of years. Russian drilling reached it in 2012. The surface above it recorded the lowest natural air temperature ever measured, −89.2°C in 1983.

Settingsubglacial lake · sealed · liquid under pressure

For the examLiquid because of pressure and geothermal heat from below. It is the analogue used for possible life under the ice of Europa and Enceladus.

Known forWhat is left of glacial Lake Agassiz

A large, very shallow remnant of glacial Lake Agassiz — the enormous ice-dammed lake whose sudden drainage about 8,200 years ago is thought to have disrupted the Atlantic overturning circulation and cooled the northern hemisphere for centuries.

Settingproglacial remnant · very shallow · eutrophic

For the examLake Agassiz's drainage is the standard example of a freshwater pulse weakening thermohaline circulation — the mechanism behind concern about Greenland melt today.

Known forChina's largest lake, and one that is growing

China's largest lake, saline and closed, at 3,200 m on the north-eastern Tibetan Plateau. Unusually among Asian lakes it has been rising since about 2005, as glacier melt and increased plateau rainfall outrun evaporation.

Settingendorheic lake · saline · high plateau

Known forThe lake fed by a river that runs backwards

The lake whose river reverses. When the Mekong floods, water is pushed back up the Tonlé Sap river and the lake expands roughly fivefold; when the flood falls it drains out again. That pulse produces one of the largest inland fisheries in the world, and upstream Mekong dams are weakening it.

Settingflood-pulse lake · seasonal reversal · great fishery

For the examThe flood-pulse reversal is unique at this scale. Mekong mainstream dams in China and Laos flatten the pulse, which is the ecological argument against them.